1. Field of the Invention
This invention relates to an intelligent card playing gaming system.
2. Background Art
Existing electronic casino games (slot machines) are available in which one player plays against a predetermined criteria that determines whether the player wins. One such game that is prominent in a casino or other gaming environment is referred to as video poker. In video poker, the player is dealt a hand of cards which is evaluated against a payoff table. Thus, the player is pitted against static, predetermined hand rankings. If the player's hand exceeds a threshold ranking, the player wins the amount indicated for the threshold. The player does not play poker against another player.
In Bridgeman et al, U.S. Pat. No. 5,046,736, a multi-player poker slot machine is described. One player is a person and the other player(s) is simulated by the slot machine system. The real player initiates all of the actions in the game while the simulated player merely responds by imitating each action of the player. There is no ability or intelligence of the simulated player to develop a strategy in which the simulated player decides upon an action other than the one performed by the real player. It is therefore, impossible for the simulated player to be the initiator of the game (i.e., make the first move). Further, the real player can predict with 100% accuracy the moves that the simulated player will take thereby making it easier for the real player to out maneuver the simulated player.
The following provides a discussion of the game of poker.
Poker Basics
There are a large number of poker variations. However, certain basic concepts apply to most types of poker.
Poker hands generally consist of five cards from a 52 card deck. There are 2,598,960 different hands. The hands are linearly ordered in strength or "rank." There are nine general categories of hands, ranked as shown in Table 1.
TABLE 1 ______________________________________ Ranking by Categories Rank Name Example ______________________________________ 1 Straight flush J 10 9 8 7 2 Four of a kind K K K K 9 3 Full house J J J 3 3 4 Flush A 10 9 5 2 5 Straight 6 5 4 3 2 6 Three of a kind 10 10 10 9 7 7 Two pair A A 4 4 9 8 One pair 9 9 K 8 6 9 No pair 3 5 6 J Q ______________________________________
Within each category, hands are ranked according to the rank of individual cards, with an ace being the highest card and a 2 being the lowest card. There is no difference in rank between the four suits of cards. Table 2 shows the ranking of some example hands within the two pair category. Because the suits of the individual cards do not matter for two pair hands (the suits become relevant only for flushes and straight flushes, since all cards in these hands must be of the same suit), no suits are shown in Table 2.
Table 2 ______________________________________ Relative Ranking of Some Two Pair Hands ______________________________________ Highest AAKKQ AAKKJ AAKK10 AAKK9 *** AAQQ2 AAJJK AAJJQ *** JJ223 101099A 101099K *** 33226 33225 Lowest 33224 ______________________________________
All hands can be ranked in a linear ranking from highest to lowest. Because suits are all of the same value, however, there are multiple hands that have identical rankings. For example, there are four equivalent hands for each type of straight flush, four of a kind, or flush; there are over a hundred equivalent hands for each two pair variation, and there are over 1000 equivalent hands for each type of no-pair hand. Accordingly, although there are over 2,000,000 possible hands, there are significantly fewer possible rankings.
Poker is characterized by rounds of card dealing and betting. Numerous variations of poker exist, including "five card draw," "five card stud," "seven card stud," "hold'em," and "Omaha." The variations generally differ in the manner in which cards are dealt and in the manner in which bets are placed. Various criteria may also be used to determine the winning hand, including highest ranking hand wins, lowest ranking hand wins ("low-ball"), and high and low hands each win half ("high-low").
Typically, a game starts when each player has placed an initial bet, called the "ante," into the "pot." The term "pot" refers to the total accumulation of bets made during a game. Each player that has "anted" is dealt an initial set of cards. The number of cards depends on the particular variation of poker being played. In five card draw, each player is initially dealt five cards.
After the deal, the players have the opportunity to place bets. If a player places a bet, that bet must be matched ("called") or "raised" by each player that wants to remain in the game. A player who does not match a bet drops out of the game or "folds." A round of betting ends when either every player but one has folded, or when the highest bet or raise has been called by each remaining player such that each remaining player has paid the same amount into the pot during the round.
Each game may have several "rounds" of betting. If two or more players remain after a round of betting, either more cards are dealt, or there is a "showdown," depending on the game variation being played. A "showdown" occurs when two or more players remain in a game after the last round of betting for a game has been completed. A player wins a game of poker (also sometimes called a "hand of poker") either by having the highest ranking hand when a "showdown" occurs, or by being the last remaining player in the game after all other players have dropped out, or "folded." At a showdown, each player displays the player's hand to the other players. The player showing the hand with the highest ranking wins the pot.
FIG. 1 illustrates the sequence of events that occur in a game of five card draw poker. As shown in FIG. 1, the game begins with each player paying an ante into the pot at step 100. At step 105, each player is dealt five cards by one of the players who is referred to as the dealer. Players take turns being the dealer.
After each player has been dealt the initial set of five cards, the first round of betting occurs at step 110. In a round of betting, each player is successively given the opportunity to either "pass" (i.e. to place no bet, allowed only if no one has previously placed a bet during the round), to "call" (i.e. to pay an amount into the pot equal to the total amount paid by the immediately preceding bettor), to "raise" (i.e. to pay an amount into the pot greater than the amount paid by the immediately preceding bettor), or to "fold" (i.e. to not pay anything into the pot and thereby to drop out of the game). The betting sequence typically starts with the player to the immediate left of the dealer, and then progresses in a clockwise direction.
FIG. 2 illustrates an example of a first round of betting that may occur at step 110 of FIG. 1. In the example of FIG. 2 there are three players: player A 200, player B 205, and player C 210. Player A is the dealer. In FIG. 2, the cards dealt to each player are shown under the player's name. Thus, after the deal, player A's hand is AA762, player B's hand is KK225, and player C's hand is JJ843.
Since player B is the player to the immediate left of the dealer (player A), player B opens the betting round. Player B may pass (bet nothing), or place a bet. Player B's hand contains two pairs, which player B considers to be a good first round hand. Accordingly, as shown in FIG. 2, player B bets one "bet" at step 215. In this example, betting "one bet" means that the bettor bets the maximum betting limit allowed by the rules of the particular variation of poker game being played. Two types of betting are "limit" betting and "pot limit" betting. In limit betting, the maximum betting limit is a predetermined amount. For example, a betting limit may be $2. In pot limit betting, the maximum amount that a player may bet is the total amount in the pot at the time the bet is made, including the amount, if any, that the bettor would need to put into the pot if the bettor were calling. Other types of betting are no limit betting, and spread limit betting, in which bets are allowed within a certain range (e.g. $2-$8).
After player B has bet, it is player C's turn to act. Since player B has bet one bet, player C's choices are to match player B's bet ("call"), to raise, or to fold. Player C has a pair of jacks, which player C considers to be good enough to call but not good enough to raise. Accordingly, as shown in FIG. 2, player C calls at step 220 by placing an amount equal to player B's bet into the pot.
After player C has bet, it's player A's turn. Player A has a pair of aces, which player A considers to be good enough for not just calling, but raising. Player A therefore decides to raise player B's bet by one bet at step 225. Player A thus places a total of two bets into the pot--one to meet B's bet, and one to raise by one bet.
After player A raises one bet, the betting proceeds back to player B. Player B considers his two pair hand to be good enough to call player A's bet, but not good enough to reraise. Accordingly, player B calls at step 230 by putting one bet (the amount of player A's raise) into the pot so that the total amount bet by player B equals the total amount bet by player A.
After player B bets, the betting returns to player C. To stay in the game, player C must place one bet into the pot to match player A's raise. However, player C doesn't believe that player C's hand of two jacks is good enough to call player A's raise. Accordingly, player C decides to drop out of the game by folding at step 235.
After player C folds, there are no remaining uncalled raises or bets. Accordingly, the first round of betting ends at step 240. Thus, after the first round of betting, there are two remaining players, player A and player B.
The size of the pot in the example of FIG. 2 after the first round of betting depends on the size of the initial ante and the betting limit of the game. Table 3 illustrates the growth in the size of the pot during the round of betting illustrated in FIG. 2 for a betting limit of $1 and for a pot limit. In both cases, it is assumed that the total ante of all three players is $1.
Table 3 ______________________________________ Size of Pot for Limit and Pot Limit Poker For Example of Figure 2 Resulting Pot Resulting Pot Betting Step Action ($1 Limit) (Pot Limit) ______________________________________ 0 Ante $1 $1 1 B bets 1 bet $2 $2 2 C calls B's bet $3 $3 3 A raises by 1 bet $5 $8 4 B calls A's raise $6 $12 5 C folds $6 $12 ______________________________________
Thus, at the end of the first round of betting illustrated in FIG. 2, the resulting pot is $6 for $1 limit poker and $12 for pot limit poker.
Referring again to FIG. 1, at the end of the first round of betting at step 110, a determination is made as to whether more than one player is left in the game at step 115. If only one player is left, that player wins the pot at step 120. If more than one player is left, play continues to step 125.
At step 125, the players remaining in the game have the opportunity to discard cards from their hands and replace them with newly dealt cards. A player may discard and replace (or "draw") from 0 to 5 cards.
After the "draw" at step 125, the second round of betting takes place at step 130. The second round of betting proceeds in the same manner as the first round of betting. FIG. 3 illustrates an example of a second round of betting that occurs after the first round of betting of FIG. 2. As shown in FIG. 3, player A and player B each drew 1 card during the draw. Player A could have drawn more cards, but player A chose to draw only one card to make it appear that player A had a better hand than player A's pair of aces. Player A discarded the lowest card of player A's hand (a 2), and was dealt a 9. Player A's resulting hand as shown in FIG. 3 is AA976.
Player B, starting off with four good cards (two pairs), also drew one card, discarding a 5 and being dealt a 7. Player B's resulting hand as shown in FIG. 3 is KK227.
The betting in round 2, as in round 1, commences with player B. As shown in FIG. 3, even though player B has a fairly good two pair hand, player B chooses to "check" (i.e., "pass) at step 300. A check is equivalent to a pass, or to betting zero. The betting then proceeds to player A. Although player A's hand is not particularly strong, player A decides to bet 1 bet at step 305, hoping that player B will believe that player A has a strong hand and therefore fold. Making a bet with a weak hand that probably will not win in a showdown is referred to as "bluffing."
Player B does not fold, but instead raises player A by one bet at step 310. Player B thus pays two bets into the pot: one to meet player A's bet, and one to raise player A one bet. Player A, believing that player B's raise is a bluff, decides to reraise player B at step 315. Player A thus pays two more bets into the pot, one to match player B's raise and one for the reraise. Player B, not having bluffed, calls player A's reraise at step 320 by paying a bet into the pot to match player A's one bet reraise.
Player B's call of player A's reraise ends the second round of betting, leading to a showdown at step 325. The amount of money in the pot at the end of the second round of betting depends on whether the game is a limit game or a pot limit game. Table 4 shows the growth in the pot in the second round of betting for limit and pot limit games given the first round pot shown in table 3.
Table 4 ______________________________________ Size of Pot for Limit and Pot Limit Poker For Example of Figure 3 Resulting Pot Resulting Pot Betting Step Action ($1 Limit) (Pot Limit) ______________________________________ 0 Beginning pot $6 $12 1 B checks $6 $12 2 A bets 1 bet $7 $24 3 B raises 1 bet $9 $72 4 A reraises 1 bet $11 $216 5 B calls $12 $324 ______________________________________
As shown in Table 4, in a pot limit game, the size of the pot increases dramatically with each pot limit bet, while the increase of the pot in a limit game is more moderate.
Referring again to FIG. 1, after the second round of betting at step 130, a determination is made as to whether more than one player is left in the game at step 135. If only one player is left, the remaining player wins the pot at step 140. If more than one player remains in the game, there is a showdown at step 145. The remaining players shown their hands, and the highest ranking hand wins the pot at step 150. In the example of FIG. 3, player B's hand of two pairs has a higher ranking than player A's hand of a pair of aces. Accordingly, player A's bluffing strategy proves unsuccessful, and player B wins the pot.